The present invention relates to an airbag system for protecting an occupant of a vehicle such as an automobile in the event of a crash. More particularly, the present invention relates to an airbag system including an airbag having an interior partitioned into a plurality of chambers.
A conventional airbag system is constructed to inflate an airbag toward an occupant by a gas generator so that the inflated airbag receives a body of the occupant. Japanese Patent Publication (Kokai) No. 2000-177527 has disclosed a structure in which a lower part of an airbag is inflated at a higher inner pressure than that of an upper part for receiving a lumbar part of the occupant. FIG. 5 is a side view of a seat equipped with the airbag system. FIG. 6 is an enlarged sectional view of a section 6 of the side airbag system shown in FIG. 5.
An airbag 18 is partitioned into an upper chamber 20 and a lower chamber 22 with a seam 24. A rear end of the seam 24 is positioned slightly away from a rear rim of the airbag 18. A cylindrical gas distributor 30 is placed in a space between the rear end of the seam 24 and the rear rim of the airbag 18. A rod-like gas generator 36 is placed in the gas distributor 30. Upper and lower ends of the gas distributor 30 are formed with pipe clips 32 and 34 for fixing the gas generator 36. The pipe clips 32 and 34 seal a portion between the gas generator 36 and the gas distributor 30. The pipe clips 32 and 34 are attached to mounting sections 26 of a seat back 14.
The gas distributor 30 has upper-chamber discharge ports 42 for discharging gas from the gas generator 36 into the upper chamber 20, and lower-chamber discharge ports 44 for discharging the gas into the lower chamber 22. The lower-chamber discharge ports 44 are larger than the upper-chamber discharge ports 42. Therefore, when the gas generator 36 is activated, the airbag 18 is inflated so that the upper chamber 20 has an inner pressure about 0.5 bar and the lower chamber 22 has an inner pressure about 1.5 bars.
The side airbag system disclosed in Japanese Patent Publication (Kokai) No. 2000-177527 includes the gas distributor 30, thereby increasing a cost. In the side airbag system, the discharge ports 42 and 44 are directed forward of the seat. Accordingly, the gas from the gas generator 36 first inflates the airbag 18 forward of the seat and then inflates the airbag 18 vertically, so that the airbag 18 is inflated vertically later.
In view of the problems described above, an object of the present invention is to provide an airbag system with a simple structure at a low cost.
It is another object of the present invention to provide an airbag system in which the airbag is quickly inflated vertically.
Further objects and advantages of the invention will be apparent from the following description of the invention.